"I think when it comes to entitlements, expenses ... the Australian taxpayers have every right to know that their money is being spent wisely."

Labor backbencher Nick Champion came to Mr Thomson's defence.

"Whenever I've talked to Craig I've always found him to be very well informed about international economic issues," he said.

Speaking to reporters in Sydney later, Health Minister Tanya Plibersek said that deputy opposition leader Julie Bishop had plagiarised an essay from New Zealand businessman Roger Kerr in 2008.

"It's a bit rich for people in the coalition to be pointing fingers when they've got a deputy leader, Julie Bishop, who is a repeated plagiariser and has been caught out in parliament on more than one occasion," Ms Plibersek told reporters in Sydney.